This invention relates to location markers. More particularly, this invention is a long-lasting, effective marker that does not emit flame or smoke and may be activated during designated intervals to aid searchers find a specific location on land or at sea.
Markers have been used to designate or draw attention to a particular object or location on land and open water. Most, if not all emit relatively large flames and volumes of smoke to attract attention.
For example, one marker in inventory by some navies of the world has been designated the Mk 58 Mod 1 marine location marker which is designed for day or night use in any condition calling for long-burning smoke and flame reference point marking on the ocean's surface. It usually is used for antisubmarine warfare, but can be used for search-and-rescue operations, man-overboard markings, and as a target for practice bombing at sea. The marker produces a yellow flame and white smoke for a minimum of forty minutes and a maximum of sixty minutes. It is visible for at least three miles under normal operating conditions.
The Mk 58 Mod 1 marine location marker consists of a cylindrical tin can approximately 21.78 inches long and 5.03 inches in diameter. The can contains two pyrotechnic candles of a red phosphorus composition. The ignition end of the marker has three holes-two for smoke and flame emission and one for water to enter the Mk 72 Mod 1 seawater-activated battery. Adhesive foil disks hermetically seal the two emission holes. A reinforced adhesive foil strip with a rectangular pull ring hermetically seals the battery cavity hole. The adhesive foil seals are protected during handling and shipping by a replaceable polyethylene protective cover.
Other examples of contemporary markers are the Mk 25 Mod 2 and 3 marine location markers that are launched from aircraft or surface craft. They are launched from aircraft to provide day or night reference points for marking the course of enemy submarines in antisubmarine warfare operations. They are suitable for any type of sea-surface reference-point marking that calls for both smoke and flame for a period of 10 to 20 minutes. Mk 25 Mod 2 and 3 function identically. The only significant difference is that Mk 25 Mod 2 contains two seawater-activated batteries and two related squibs, while Mod 3 contains a single battery and a single squib.
The Mk 25 marker consists of a cylindrical outer tube about 18.5 inches long and 2.9 inches in diameter. A valve assembly is fitted into the projecting chimney at the marker's nose end. The smoke and flame are emitted from this opening. At the opposite end is a heavier aluminum base assembly to which the outer tube is crimped. The heavy base end causes the marker to float in the water with the chimney out of the water and the base in the water. Within the base assembly is a Mk 72 Mod 0 seawater-activated battery (two batteries in the Mod 2). The battery is shielded from water contact by two plugs fitted into ½-inch holes on two opposite sides of the base assembly. A rigid cover, or arming plate held in place by a retainer ring, is recessed into the base end. An arrow in the center of the arming plate indicates its safe or armed position. The words SAFE and ARMED are stamped into the base rim. Also, a machined notch in the rim at the armed position helps during night use. When the arming plate is in the safe position, it physically blocks the base plugs internally to prevent them from being accidentally pushed in. When in the armed position, the arming plate no longer blocks the base plugs, allowing them to be pushed in at the appropriate time. A black rubber O-ring circles the base assembly approximately ¼ inch from the crimp, which holds the outer case. To activate the seawater battery, the base plugs are pushed in before the marker is actually launched. An electric squib ignites the marker, and the seawater-activated battery (two batteries and two squibs in Mod 2) supplies power. When the marker enters the water, seawater enters the battery cavity and serves as an electrolyte, causing the battery to produce a current that activates the squib. The squib ignites the starter mix, which, in turn, ignites the red phosphorous pyrotechnic composition.
Gas buildup forces the valve assembly from the chimney in the nose, and yellow flame and white smoke are emitted. Burning time averages 13.5 to 18.5 minutes. Although this marker is normally used in seawater, it can be used in inland bodies of fresh water by using table salt.
Thus, in accordance with this inventive concept, a need has been recognized in the state of the art for a long-lasting, effective marker that does not emit flame or smoke and may be activated at designated times to aid searchers find a specific location on land or at sea.